At the risk of sounding repetitious, I too suggest you carry the weapon on your person. Since you don't wear a jacket you have a few basic options:
Inside the waist holster (IWB), wearing a golf shirt un-tucked for concealment, OR there are IWB holsters that allow you to tuck the bottom of the shirt in..
My brother, who operates a small catering service, also has to go into less than desirable neighborhoods, carries a J frame S&W in a belly band with a pouch. He prefers that because he can get to his weapon either standing or setting.
Another option is a pocket holster and small weapon like the Kel-Tec P3AT or the Ruger LCP. Both are .380 cal. but there ares some pretty good self defense ammo out there. Given your size, you could even comfortably carry a couple different compact makes of 9mm's in your pocket.
I would caution against ankle holsters as they make it very difficult at best to get to your weapon in a rapid manner. IMHO they are worse than the bag idea. However, your holster problem is just beginning. Have you looked at all the manufacturers of holsters out there?
The most important thing you must decide is manner of carry, then find a weapon that fits YOU and then the carry method. If both the weapon and holster are not completely comfortable, you will find yourself "forgetting" to take it. According to a wise man named Murphy, that is when you will need it the most. My best advice don't try to do this in one or even two days. Talk to people at your local gun store and get several opinions there, as you are here. And Oh Yeah welcome to concealed carry and the decisions that go with it.